Marine propulsion unit



Jan. 21, 1969 J, R, wYNNE ET AL MAHINE PROPULSION UNIT Sheet Of 6 FiledSep'L' 13, 1967 Jan.21,1969 J R,WYNN Em 3,422,789

MARINE PROPULS ION UNIT Filed Sept. 15, 1967 Sheet 2 of 6 'FIG.6

INVENTORS James R. /fl/yrme BY (fa/727 (if/ Jan. 21, 1969 1. R. wYNNEETAL MARINE PROPULSION UNIT Sheet 3 of6 Filed Sept. 13, 1967 Jan.21,1969J R,WYNNE ETAL 3,422,789

MARINE PROPULS ION UNIT Sheet Filed Sept. 13, 1967 INVENTORS James P.Wg/rme By dblm D, Gil! "47'7'0RNEV J. R. WYNNE ETA!- MARINE PRoPUsIoNUNIT Jan. 21, 1959 Sheet 5 of 6 Filed Sept. 13, 1967 Jan. 21, 1969 i J,R WYNNE ET AL 3,422,789

MARINE PROPULSION UNIT Filed Sept. 13, 1967 Sheet of 6 :NvBNToRs Jama?P. /4/ ;ma By Jbm D. l

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I ArmR/VEV United States Patent O 3,422,789 MARINE PROPULSION UNIT JamesR. Wynne, Miami, and John D. Gill, Coral Gables, Fla., assignors toWynn-Gill Associates, Inc., Miami, Fla., a corporation of FloridaContinuation-in-part of application Ser. No. 455,171, May 12, 1965. Thisapplication Sept. 13, 1967, Ser. No. 671,914 U.S. Cl. 115-12 14 ClaimsInt. Cl. B63h 21/24 ABSTRACT OF THE DISCLOSURE A marine propulsion uniton a planing boat having a downwardly extending drive shaft through thetransom opening with the propeller being substantially below the at restwater line, and a housing having an inlet below the planing surface, anoutlet rearwardly thereof and a conical portion between inlet and outletsurrounding the propeller. Flow straightening means including a pair ofhorizontal vanes having oppositely curved portions facing and opposingthe rotational components of the water from the propeller are disposedrearwardly of the propeller, and a rudder having oppositely curved vaneportions is supported by the housing and a portion of the propeller hubadjacent the outlet. The housing is provided with side deflecting vanesforwardly of the propeller to defiect water laterally through sideopenings in the housing to provide steerng while backing down.

Cross reference to related application This application is acontinuation-in-part of our copending application Ser. No. 455,171,filed May 12, 1965, entitled Marine Propulsion Unit, and now abandoned.

This invention relates to marine propulsion units and more particularlyto novel and improved marine propulsion units particularly adapted foruse with boats having stern mounted engines with the engine drive shaftextending rearwardly and outwardly through the transom of the boat.

There have been many prior arrangements for propelling a boat by meansof an internal combustion engine located within the hull of the boat.Recently, considerable development has taken place in marine propulsionunits of the type associated with boats in which the engine is locatedclosely adjacent the stern transom of the boat. In some units of thistype the engine is drivingly connected to a multi-stage pump generallyof the axial flow type with water being drawn upwardly through anopening in the bottom of the boat and discharged rearwardly through anopening in the stern transom of the boat. In other devices associatedwith stern located engines, the engine is connected to an outboardpropeller housing supported aft of the transom of the boat with meansbeing provided for moving the housing to move the propeller generallyvertically to facilitate placing the boat on or removing it from atrailer. In either of the types of propulsion units generally describedabove, there is considerable, and in some cases relatively complex,structure associated with the propulsion mechanism driven by the engineas well as the means for mounting this mechanism. Also, in the case ofthe engine-pump arrangement, the overall unit has a reduced overallefiiciency inasmuch as the water drawn into the pump must be lifted asubstantial vertical distance. Additionally, such engine-pump unitsusually produce a thrust which is substantially independent of the speedof the boat. This requires a large percentage of engine power to drive aplaning boat over the characteristic hump in its drag curve 3,42Z,789Patented Jan. 21, 1969 in order to get the boat up onto plane. Suchunits also often encounter difficulty when Operating in choppy waterinasmuch as air entering the inlet of the pump causes thrust to be lostand appreciable time is often required to clear the air, during whichtime the engine overspeeds. In addition, engine-pump units, when used insalt water, have a tendency for the internal parts thereof to foul withmarine growth thus reducing the overall efiiciency of the pumping unit.

Accordingly, it is an object of the present invention to provide in aboat having an engine mounted adjacent the stern transom thereof, anovel and improved propulsion unit disposed outboard of the transom andextending only a short distance below the planing surface of the boat.

It is a further object of the present invention to provide a novel andimproved propulsion unit of the type described in which the thrust ofthe overall engine-propulsion unit combination will increase with speedto facilitate the obtaining of planing speed and reduce the powerrequired to place the boat on plane.

It is a further object of the present invention to provide a novel andimproved propulsion unit of the type described which will operateefliciently in choppy as well as calm water.

It is a further object of the present invention to provide a novel andimproved marine propulsion unit of the type described which isrelatively simple and economical in construction and which may readilybe mounted on and disassembled from the transom of a boat.

It is yet another object of the invention to provide improved steerngmeans for steerng a duct type propulsion unit while backing down.

The novel features which are believed to be characteristic of thisinvention are set forth with particularity in the appended claims. Theinvention itself, however, both as to its organization and method ofoperation, together with further objects and advantages thereof, maybest be understood by reference to the following description taken inconnection with the accompanying drawings, in which:

FIG. 1 is an isometric view of a propulsion unit constructed inaccordance with the present invention and mounted on the stern transomof a planing boat;

FIG. 2 is an enlarged, longitudinal cross-sectional view of the unit ofFIG. 1;

FIG. 3 is an enlarged cross-sectional view of a portion of theinstallation of FIG. 1 illustrating the mounting of the unit on a boatand the connection of the same to an engine;

FIG. 4 is a cross-sectional view substantially along the line 4-4 ofFIG. 2;

FIG. 5 is a bottom view of the unit of FIG. 2;

FIG. 6 is an enlarged cross-sectional view substantially along the line6-6 of FIG. 4;

FIG. 7 is an enlarged cross-sectional view substantially along the line7-7 of FIG. 4;

FIG. 8 is a perspective view of a propulsion unit of the type of FIGS.1-7 modified by the provision of deflecting vanes for effective steerngwhile backing down;

FIG. 9 is a Vertical sectional view taken along the center line of theunit of FIG. 8;

FIG. 10 is a schematic representation, applicable to the units of FIGS.8, 9, 11, 12 and 13, explanatory of the functions of the steerngfeatures thereof;

FIG. 11 is a side elevation of a further modified propulsion unit andthe engine therefor, including advantageous means for disposing ofengine exhaust gases;

FIG. 12 is a sectional view of the propulsion unit and a portion of theboat, taken along the line 12-12 of FIG. 11; and

FIG. 13 is a rear view of the unit of FIG. ll, with certain partsomitted for clarity, and including the engine shown in broken lines toillustrate the position thereof relative to the unit.

With reference to the drawings, and particularly FIGS. 1-3, a preferredembodiment of a marine propulsion unit constr'ucted in accordance withthe present invention is shown `mounted on the stern transom of a boatof the type having a planing surface 12 on the underside of the bottomof the boat and extending forwardly from the lower edge of the transom10. The boat is of a conventional construction and has mounted withinits hull an inboard engine (not shown). The propulsion unit comprises anoutboard housing generally indicated at 14 and mounted on the outboardside of the transom 10 'so as to extend rearwardly of the transomparallel to the centerline of the boat. As best shown in FIG. 2 the unitfurther comprises a propeller 16 mounted by a splined connection to theouter end of a propeller shaft 18. The propeller is held on the shaft 18by a retaining nut 20 threadably engaged over the outer end of the shaft18. The shaft 18 extends through an opening 22 in the transom. Theopening 22 is disposed substantially below the upper edge of the transomand relatively close to the bottom of the transom. The shaft 18 isinclined at a substantial angle to the general plane of the planingsurface 12, and in the specific embodiment shown, the shaft angle isapproximately 15 degrees. The shaft 18 is disposed within a sleeve 24arranged telescopically and coaxially over the shaft. The sleeve 24terminates at its outer end closely adjacent the propeller 16. The outerend of the sleeve 24 is held in radially spaced relation to the shaft 18by a self-lubricating bearing 26. The sleeve 24 extends inwardly of theboat through the opening 22 inthe transom and terminates a shortdistance inboard of the transom. Mounted -on the forward portion of thesleeve 24 is an elongated collar or tube 28. The collar 28 is disposedwithin the opening 22 in the transom and extends outwardly of theopening in opposite directions. The outer end of the tube 28 is fixed tothe sleeve 24 in water sealed relation by suitable means such as a weld.

The tube 28 is further fixed relative to a mounting plate 30, which asmost clearly shown in FIG. 1, is adapted to be fixed, such as by bolts,to the outboard surface of the transom 10, to support the sleeve 24 andcollar 28 in fixed relation relative to the boat. The plate 30 extendsentirely about and radially outwardly beyond the opening 22 in thetransom and is preferrably fixed to the transom in water tight relationby suitable means such as bedding compound. The collar 28 is furthersupported relative to the mounting plate 30 by a stiffner or gusset 32which is fixed to the mounting plate and collar and is disposed withinthe opening 22 in the transom. A flange 34 is mounted in fixed relationon the inner end of the collar 28 which is disposed forward of thetransom and within the boat. The flange 34 is bolted to a second fiange35 which is on a collar 37 disposed co-axially over the shaft 18. Thecollar 37 forms the outer race for a ball- 'bearing 36 for the shaft 18.The inner race of the bearing 36 is provided by a sleeve 38 arrangedco-axially over and about the shaft 18 and fixed to the shaft 18 bymeans of an intermediate sleeve 40. The shaft 18 extends forwardly ofthe boat beyond the bearing 36 for connection by suitable means (notshown) to the drive shaft of the engine. Thus, the shaft 18 is rotatablysupported intermediate its ends by the ball-bearing 36, this bearingbeing located closely adjacent the inboard side of the transom and being'supported on the mounting plate 30 which in turn is mounted on thetransom. The inner or forward end of the propeller shaft is adapted tobe rigidly connected to the crankshaft of the engine and extends inalignment with the engine crankshaft. A watertight shaft seal is'provided between flange 34 and the shaft as shown at 39.

With reference to FIGS. 1, 2 and 4 the outboard housing 14 is fabricatedfrom sheet metal and comprises a generally conical portion 42 whichsurrounds the propeller 16 and has an axis lying coincident with theaxis of the shaft 18. The greater diameter end of the conical 'housingportion 42 is approximately in registry with the for- Ward end of thepropeller 16 and the conical portion 42 tapers rearwardly to terminate asubstantial distance behind the propeller. The housing 14 forward of theconical portion 42 is faired into a generally flat wall 44 which isinclined forwardly and downwardly from adjacent the upper forwardportion of the conical portion 42 and terminates at the base of themounting plate 30 where it is fixed thereto by suitable means such aswelding. The wall 44 is provided with an opening through which the tube24 extends in water sealed relation. The sides of the outboard housing14 forward of the conical portion 42 are curved downwardly terminatingin a bottom wall 46 which, as shown in FIGS. 2 and 5 is provided with aninlet opening 48 which is generally triangular in Shape having its baseextending along the base of the mounting plate 30 and its apex disposedclosely adjacent the large diameter end of the conical portion 42 of theoutboard housing. A generally flat stifener plate 45 extends fromadjacent the upper end of the wall 44 over the shaft sleeve 24 and toadjacent the top of the mounting plate 30. A Vertical stiffener 47extends from the underside of the plate 45 to the sleeve 24 for supportof the portion of the sleeve between the mounting plate 30 and the wall44.

In accordance with one aspect of the invention, the general plane of theinlet opening 48 is inclined relative to the general plane of theplaning surface 12 of the boat at a substantial angle. In the specificembodiment shown, the general plane of the opening 48 is inclineddownwardly and rearwardly from the mounting plate 30 at an angle ofapproximately 15 degrees to the general plane of the planing surface 12of the boat, or in other words extends generally parallel to the axis ofthe shaft 18. Accordingly, as the boat is moved through the water andparticularly at speeds below but approaching the planing speed of theboat, the boat will be inclined with its bow up so that the generalplane of the opening 48 will be inclined at a very substantial degreecorresponding to the inclination of the opening relative to the planingsurface of the boat plus the inclination of the boat itself relative tothe `line of the movement of the boat. In this manner, water will beforced into the opening 48 with a very substantial ram effect so as tocompletely fill the duct formed by the interior of the outboard housing.Even after the boat is at planing speed, and its *bow angle has reduced,the general plane of the opening 48 will still be inclined a substantialamount relative to the direction of movement of the boat through thewater, and the faster the boat goes the greater will be the ram effect,thus providing an increase in the flow rate of water and a resultantimprovement in propeller efliciency. The greater inclination of thegeneral plane of the opening 48 at lower speeds approaching planingspeed of the boat assures that a substantial ram effect will occur inthis speed range to assist in placing the boat on plane much easier thanif the inlet opening 48 were not inclined substantially relative to thedirection of movement of the boat.

The outer diameter of the propeller 16 passes closelyl adjacent theinner wall of the conical portion 42. In this connection, the tips ofthe propeller blade are generally rectangular in planform but slightlytapered in order to correspond to the conical cross-section of thesurrounding portion of the outboard housing. With reference to FIGS. 4,6 and 7, disposed aft of the propeller 16 and closely adjacent theretoare a pair of horizontally extending flow straightening vanes 50, 52.The vanes 50, 52 are mounted at their outer ends on a removable portion54 of the outboard housing 42. As most clearly shown in FIG. 1 theremovable housing portion 54 is generally Semi-conical in configurationand Igenerally forms the top half of the conical portion 42 of theoutboard :hosuing The removable portion 54 is adapted to be mounted onthe remainder of the outboard housing 'by a plurality of screws disposedabout the sides and forward end of the removable portion 54. By removingthe portion 54 of the outboard housing, access may be vreadily had tothe propeller 16 for repair or replacement thereof and further theremovable portion 54 facilitates clearing of the inside of the outboardhousing as well as painting of the same with antifouling paint.

The inner ends of the vanes 50, 52 are supported on a hub 56 which isgenerally conical in shape and tapers toward the after end of thehousing 14. The forward end -of the hub 56 is of the same outer diameteras the after end of the propeller hub 58 which is generally taperedforwardly toward the mounting plate 30. The hubs 56, 58 thus provide astrearnlined contour. In accordance with another aspect of theinvention, the vanes 50 and 52 may be mounted on the remova-ble portion54 of the outboard housing and on the hub 56 by means of pivots, as at60, with the axis of the pivots being aligned and extending at rightangles through the lon-gitudinal axisof the conical portion 42 of theoutboard housing. The vanes 50, 52 may thus be adjusted lfor bestefliciency about the axis of the pivots 60. Suitable means (not shown)associated with the pivots 60 are provided to lock the vanes inangularly adjusted position about their pivotal axis. The general planesof the vanes 50, 52 extend generally laterally across the conicalportion 42 of the outboard housing and as shown in FIGS. 6 and 7, thevanes 50, 52 have a cross-section which is such that the vanes Will tendto straighten the flow of water passing from the after end of thepropeller 16 so as to tend to remove the rotational component of thewater about the axis of the shaft 18 and tend to direct the wateraxially of the conical portion of the outboard housing.

Disposed aft of the vanes 50, 52 and relatively closely adjacent theretois a rudder generally indicated at 62. The rudder 62 comprises a pair ofvertically extending vane portions 64, 66 fixed at their inner ends on ahub 68 the outer contour of which forms a continuation of the vfairedstreamlined contour of the hub 56 for the fixed vanes 50, 52. TheVertical vane portions 64, 66 of the rudder are curved as shown in FIG.4 so that the rudder also acts as a flow straightener to remove therotational components of the water and direct the water axiallyoutwardly of the exhaust opening at the after end of the outboardhousing. The upper rudder vane portion 64 has an upwardly extendingprojection 70 which is rotatively received within a generally verticallyextending boss 72 on the removable housing portion 54. With reference toFIG. 2, the hub of the rudder is pivotally supported in a sphericalbearing 74 received within an opening extending inwardly from theforward end of the hub 68. The outer race of the bearing 74 is supportedon the hub 56, the after end surface of which is dished or concaved topermit pivotal movement of the hub 68 relative to the hub 56 withoutinterference 'between the two. The outer tips of the rudder vanes aretapered inwardly and rearwardly of the outboard housing so as to permittheir reception within the outer end portion of the generally conicalhousing portion 42 which is preferably slightly out of round by beingfiattened top and bottom to permit movement of the blade about theirpivotal axis a sufficient amount without interference with the housing14. It will also be observed that the rudder extends a substantialdistance rearwardly beyond the after end of the outboard housing.

Straightening the flow, the forward portions 64' and 66' of the ruddervane portions, and the forward portions 50' and 52' of the flowstraightening vanes provide forward thrust on the boat.

With re-ference to FIG. 2, the projection 70 on the upper rudder vaneportion 64 terminates in a post which is externally threaded. A quadrant78 is mounted on the post 77 for rotation therewith and is maintained inassembly with the post by means of a nut threaded over the outer end ofthe post. The quadrant 78 is preferably keyed or splined to the post 77.With reference to PIG. 1, the rudder may be moved by means of cables 80,82 which extend from within the boat through openings in the transom andmounting plate 30 and rearwardly generally along the top of the outboardhousing 14. The cable which is on the starboard or right side of thehousing extends around a sheave 84 rotatably carried by the removablehousing portion 54 and disposed on top of the removable portion 54. Thecable 80 then extends about the arcuate surface of the quadrant 78 andis anchored to the quadrant adjacent the leftward end of the cablesupporting surface of the quadrant as viewed in FIG. 1. The cable 82extends rearwardly of the housing 14 and around the sheave 86, alsomounted on top of the housing portion 54. The cable 82 then extendsalong the arcuate cable supporting surface of the quadrant 78 in anopposite direction to the cable 80. The cable 82 is anchored on theright- Ward end of the quadrant as viewed in FIG. 1. Accordingly, itWill 'be apparent that movement of the cable 80 in a -direction inwardlyof the 'boat will effect a clockwise movement of the quadrant, as viewedin FIG. 1, to provide a correspondng movement of the rudder to effectturning of the boat to the left. The opposite result will be achievedwhen the cable 82 is moved inwardly of the boat.

Thus, it will be seen that there has been provided a novel and improvedmeans for propelling a boat wherein a conventional marine inboard enginemay be used to drive directly the propeller shaft without anyintervening right angle drives or the like. The propeller shaft isconnected either directly to the inclined engine or to the output shaftof a conventional gear reduction carried by the engine. The entirepropulsion unit of the outboard housing and propeller and otherassociated elements carried by the housing are mounted as a unit on thetransom simply by extending the propeller shaft through the sternopening in the transom and then bolting the mounting plate 30 to thetransom. This eliminates the need for a shaft log, shaft stunt etc.necessary to the usual inboard engine installation. The outboard housingprojects downwardly and rearwardly of the boat an amount suflicient toachieve the desired ram effect of water entering the inlet 48 of thehousing, While at the same time the unit does not pro- ]e ctsufliciently below the bottom of the boat to interfere with operation inshoal Waters and eliminates the need for the provision of mechanisms forvertically moving the outboard housing upwardly to permit launching andrecovery from and on a boat trailer. In this latter connection, theoutboard housing is disposed below the general plane of the planingsurface 12 of the boat an amount correspondng to a location of thepropeller such that the `general plane of the planing surface of theboat passes through the propeller shaft axis closely adjacent the centerofrotation of the propeller. Thus, the outboard housing projects belowthe planing surface a distance approximately equal to the radius of thepropeller.

The propulsion unit of this invention also has the advantage of beingadapted for use with a boat in which the engine is located relativelyclosely adjacent the stern transom, thus achieving maximum efiiciencyfor planing hulls, and at the same time assuring that the engineoccupies only a minimum of usable space Within the boat. The generallyswept back shape of the intake duct tends to encourage the shedding ofweeds and other debris quite effectively. However, if desired the inletopening 48 may be protected with a grill or a screen. Inasmuch as thegeneral plane of the planing surface 12, or after bottom portion of theboat, intercepts the propeller axis at or cosely adjacent the centerrotation of the propeller, it will be apparent that when the boat is atrest the duct or passage through the outboard housing will be for themost part filled with water. At least over one-half of the propellerwill be submerged. In other words the water line of the boat when theboat is at rest is at least at a level with, if not above, the center ofthe propeller. Thus, even at slow speeds the housing will tend to becompletely filled with water thusreducing, if not eliminating, pumpinglosses present in installations in which the water must be lifted asubstantial distance by a pump before water reaches the pump itself. Asnoted above when the boat is moving through the water at speedsapproaching but below planing speeds, and when the boat is at planingspeed, water will be rammed into the inlet of the outboard housing toassure that the housing will be completely full. When the boat isoperating in choppy water, if any air enters the inlet of the outboardunit it will be removed substantially immediately by the ram effect assoon as the inlet 48 is again submerged. Thus, no loss of thrust will beencountered when Operating in choppy water, and there Will be little ifany tendency for the propeller to cavitate. Also, the location of theinlet 48 aft of the transom assures that the opening 48 will remainsubrnerged a substantially greater portion of the time when the boat isOperating in choppy water than would be the case if the inlet werelocated in the hull of the boat substantially forward of the transom.Inasmuch as water is fiowing through the outboard housing at all timesthat the boat is in forward motion, steering control may be maintainedeven if engine stops. lt will also be observed that the housing 14extends parallel to the centelrline of the boat so that the portion ofthe housing in the water provides directional stability at high speedsby acting as a skeg or keel.

In accordance with the invention, the outboard housing should beinclined relative to the planing surface of the boat an amountsuflicient to assure that the opening 48 will be inclined relative tothe direction movement of the boat sufliciently to achieve the rameffect which is desired. The effectivearca of the inlet opening 48 is,of course, suflicient to permit a flow of water adequate to fill theduct at normal Operating speeds. At the same time a compromise has beenachicved between allowable installation angle of the engine, clearancebetween the engine and bottom of the boat, propeller size and overhangof the outboard housing aft of the stern so that water entering theinlet 48 is not redirected an appreciable amount before it encountersthe propeller 16. The placing of the propeller relative to the inletopening 48 such that when the boat is at planing speed water enteringthe inlet 48 flows generally directly and in a straight line to thepropeller 16 to a large part eliminates -losses due to turning of thewater as would occur in installations where the wateris directed firstvertically upwardly within the boat and then at right angles through apump or the like. The propeller is located at or just aft of thejuncture of the larger diameter end of the conical housing portion 42and the upper end of the inclined forward surface 44 of the housingwhich in Cooperation with the conical portion lprovides a bend in thepassage through the housing on the order of about 30 degrees. Theplacing of the propeller in or just aft of this bend in the duct willresult in the propeller blades tending to guide the flow of water aroundthe bend, and thus the propeller blade acts as guide vanes to prevent aturbulent mixing of axial and radial flow of the water as it is turnedto flow through the conical portion of the duct.

The water passing from the propeller will, of course, have both axia-land rotational movement. The rotational component of movement of thewater is in part removed by the horizontal stator vanes 50, 52 and inpart by the rudder vanes 64, 66. Thus, it will be seen that generallyspeaking a four bladed stator is provided with the vanes of the statorextending at right angles to each other. Two of the stator blades orvanes 50, 52 may, as noted above may be pivotably mounted so as to serveas means for adjusting the trim of the boat. The other two flowstraightening vanes also serve as the rudder for the vessel. The use ofthe rudder as straightening vanes reduces the number of components inthe flow path of the water and thus minimi'zes losses due to skinfriction and also reduces the length of the duct with an attendanteconomy of material and component parts.

When it is desired to repair or replace the propeller the removablehousing portion 50, 54 is removed. Inasmuch as the rudder and fixedvanes 50, 52 are mounted on the removable portion 52, they will beremoved at the same time, thus permitting free access to the propeller.At the same time the entire interior of the outboard housing will bereadily accessible for- Cleaning or the applying of antifouling paint. r

Referring now to FIGS. 8 and 9, there is shown a marine propulsion unitof the jet type 'as described in connection with FIGS. 1 through 7, butto which reverse steering means are added. The reverse steering meanscomprise a pair of defiecting vanes, of which vane is seen in FIG. 8 andvane 91 in FIG. 9, and which are so disposed as, preferably, tosubstantially close respective openings in the respective side Walls 92and 93 of the duet 14 through which the water is impelled by thepropel'ler or impeller 16.v In order forthe jet unit to drive the boatin reverse, the shaft 18 is arranged to be operable selectively inforward andreversedirections of rotation (such as by an engine withforward, neutral and reverse transmission as shown in FIG. 11). Thedefiecting vanes 90 and 91 are so pivotally mounted to .the shell bymeans of -pivots 94 and 95, as seen in FIG. 9, that. each is swingablefrom a position in alignment with the respective side wall, andpreferably closing the side wa-ll opening, such as opening 96, into areverse steering position in which the rearward edge,- suchas edge 97 ofdefiecting vane 91, is swung inwardly of the d-uct and in which thevane, accordingly, deflects water laterally outwardly from the ductthrough the respective side wall opening.

Each vane is arranged to be swung for steering from a convenient remotelocation, such as from the usual pilot's control station within theboat, and the steering means shown comprises a respective sheave fixedlyconnected to each vane. The sheaves 98 and 99 are thus connected tovanes 90 and 91, respectively, and steering cable 80, 82 is drivinglyentrained on each pulley. As the cable is pulled in o ne direction therear edge of each defiecting vane'and' the rear edge of the rudder areunitarily swung in the same direction. Thus if the port cable is pulled,the rear edge 97 of vane 91 swings to starboard and inwardly of theduet, while the rear edges of the rudder 62 and of vane 90 also swing tostarboard.

FIG. 10 illustrates schematically, in top view, the steering action.Arrow 100 represents the flow of water in duct 14 during forward driveof propeller or impeller 16. The rudder 62 is shown in full lines in aposition to steer the boat to port. Deflecting vanes 90 and 91 have somesteering effect during forward driving of the boat, vane 91 defiectingwater laterally o utwardly to port through the opening 96 and vane 90tending to defiect water inwardly into the duct through the respectiveopening 101. To steer to starboard, the rudder and defiecting vaneswould, of course, `be swung into the broken line positions 62', 90', and91', respectively.

For reverse operation, to back down the boat, the impeller rotation isreversed to cause water flow in the direction opposite to arrow 100. Tobackdown to port, the rudder and vanes Would be swung into their fulllines position, with the rearward edge 102 of vane 90 disposed inward ofthe duct, whereby water is defiected to flow laterally in a starboarddirection through opening 101. The flow past rudder 62 tends to urge theboat stern to port, while there is a tendency for water to flowforwardly and generally to starboard along vane 91 and to enter throughopening 96 into the duct, thereby tending further to urge the stern toport. It will be apparent that during backing down the vane having itsrear edge disposed inwardly of the duct, such as is edge 102 of vane 90in the full line position in FIG. 10, this vane being upstream of theimpeller, intercepts a strong, positive flow of water which the vanethen forces out through the corresponding opening 101. Water entersopening 96 because rear vane edge 97 is outwardly of the duct, but underthese conditions, the water so entering opening 96 is the result ofinduced rather than positive fiow and, accordingly, the steering effectof vane 91 While backing down to port is somewhat less than the effectof vane 90. During forward propulsion, since the deflecting vanes areforward of the impeller, all of the fiow through openings 96 and 101would be induced fiow rather than positive fiow, while the fiow throughopening 101 (the vanes and rudder being in their full line positions ofFIG. 10) would be somewhat greater than the fiow through opening 96. Thesteering effect of rudder 62 during forward operation will be normallygreater than the effect of the 'deflecting vanes 90 and 91, unless therudder is made smaller than desired size or its quadrant is too large inproportion to the diameters of sheaves 98 and 99.

While it is preferable that the vanes 90 and 91 be disposed andproportioned to substantially completely close their respective openingsduring straight operation of the boat for Optimum duct efliciency, itwill be apparent that steering can be accomplished even if the openingsare not so 'closable. Thus even if the openings are not closed when thevanes and rudder are aligned with the duct walls and parallel to theboat axis, the vanes and rudder would have no course changing effect.

The positions of vanes 90 and 91 and of rudder 62 for straight steeringare omitted from the diagram of FIG. 10, but it will be apparent thatfor straight steering each would be parallel to the arrow 100, withvanes 90 and 91 closing openings 101 and 96, respectively.

FIGS. 11, 12, and 13 show a further modified propulsion unit so arrangedthat the ideflecting vanes for reverse steering are lower in the water,and providing for an engine exhaust as a part of the outboard drive unithousing.

The propulsion engine 103 is mounted within the boat forwardly oftransom 110 and comprises a drive shaft 118 extending through thetransom and operated in forward and reverse directions through aforward-neutral-reverse transmission 119 Controlled through cable 121from the pilofs station. Exhaust pipes 123 and 123' lead from the engineto a respective jacket or housing, such as jacket 125 and thence througha plate 127 attached to the transom by lbolts 129 and through a transomopening 131. Plate 127 closes opening 131 and also supplies support tooutboard housing 114 to attach it to the boat.

The housing 114 is generally similar to housing 14 previously describedand has a forward intake opening 133, a rearward jet opening 135, animpeller 116 and a rudder 162. straightening vanes may be providedwithin the duct or housing 114 as described hereinabove in connectionwith FIGS. 1-7, and rudder 162 may be shaped as described in connectionwith rudder 62.

The housing or shell 114 is disposed for the most part below the planingwater line of the hull, and the intake area of the forward opening 133may be generally projected as at 107.

Defiecting vanes 190 and 191 are pivotally mounted to the side walls 192and 193 of the housing'jin the manner previously described for vanes 90and 91, and swingable in the same manner by means of sheaves or pulleys,such as sheave 198 and vane 190, engaged by steering cable 180. Cable180 extends from a pilot station in the boat along idler sheaves, suchas idler sheaves 85 and 184, to a connection with steering quadrant 178for rudder 162. The vanes 190 and 191 swing with rudder 162 as describedin connection with FIG. 10, and FIGS. 8 and 9. It will be understoodthat elements 110, 114, 116, 118, 162, 178, 180, 184, 190, 191 and 198correspond to, and eXcept to the extent specifically otherwise describedmay be substantially identical in construction and function to elements10, 14, 16, 18, 62, 78, 80, 84, 90, 91 and 98 as previously described.

Shell or housing 114, however, is further provided with side exhaust gaspassageways indicated in broken lines at 139 in FIG. ll. The jacket 125opens into passageway 139, as does the exhaust pipe 123 at a pointsomewhat 10 aft of transom 110. The jacket may, if desired, be suppliedat its forward portion forward of the transom with water for cooling theexhaust in a well known manner, and the water and exhaust gases then mixwithin passageway 139 aft of the transom. Alternatively, the exhaustpipe may connect directly into jacket 125 with no water supplied, andthe jacket may be no more than an enlarged and generally flattened ornarrower continuation of the exhaust gas passage.

While only one passage 139 is shown on the star-board side of housing114, it will :be understood that a similar passage is arranged on -theport side for jacket 125' and pipe 123'. The passages preferably meetgenerally below impeller 116 and the exhaust gases, or the gas and watermixture if the jackets are supplied with water, issue from a generallysubmerged narrow arcuate exhaust opening 141 rimm'ing the lower portionof the housing 114 at its rear outlet 135.

What is claimed as new and what it is desired to secure by LettersPatent of the United States is:

1. In a marine propulsion unit mounted on a planing boat having a sterntransom and a planing surface, a propeller shaft extending rearwardlythrough an opening in said transom and parallel to the centerline of theboat, the axis of said shaft being inclined downwardly and rearwardly ofsaid planing surface, a propeller mounted on said shaft rearwardly ofsaid transom with at least a substantial portion of the propeller beingbelow the at rest water line of the boat and being partially 'below the`general plane of said planing surface, a propeller housing mounted onand fixed to said transom and extending rearwardly thereof parallel tothe longitudinal centerline of said boat, said housing including agenerally conical portion disposed co-axially over said shaft andclosely surrounding said propeller, said conical portion taperingrearwardly of the propeller and 'being provided at its rearward end withan outlet opening, and means providing a water inlet opening in saidhousing forward of said propeller and disposed 'below said planingsurface, the general plane of said inlet opening being inclinedsubstantially downwardly and rearwardly of said transom and inclineddownwardly to the -general plane of said planing surface, fiowstraightening means disposed within said conical portion of the housingrearwardly of said propeller and including a pair of horizontal vanessupported by said conical portion of said housing, a central propellerhub portion extending in alignment with said shaft and stationary withrespect to said shaft and propeller, said central hub portion beingconnected to said pair of horizontal vanes, said flow straighteningmeans further comprising a rudder supported 'by said housing on agenerally Vertical axis and partially extending into said rearward endof said housing conical portion, an end propeller hub portion mounted tosaid rudder for pivotal movement therewith, said end hub portion beingdisposed in general alignment with said central hub portion and Ibeingat least partially within said rearward end of said housing conicalportion, joint means between said end hub portion and central hubportion for maintaining said central hub portion in its position alignedwith said shaft during pivoting of said end hub portion with said rudderwhile steering the boat.

2. In a marine propulsion unit mounted on a planing boat having a sterntransom and a planing surface, a propeller shaft extendng rearwardlythrough an opening in said transom, a propeller mounted on said shaft,at least a substantial portion of the propeller being below the at restwater line of the boat, a housing mounted on and fixed to the transomand extendng rearwardly thereof, said housing including a portionclosely surrounding said propeller and extending rearwardly thereof toprovide a water Outlet for the housing, means providing a water inletopening in said housing forward of said propeller and lbelow saidplaning surface, and fiow straight ening means disposed rearwardly ofsaid propeller and including a plurality of curved vanes mounted inselected positions within said housing and extending generally radiallyof and spaced angularly about the axis of said shaft with the curvesthereof facing and opposing the rotational component of the fiowingwater from said propeller, said plurality of curved vanes including apair of generally horizontally extending oppositely curved vanes, andmeans mounting said vanes for selective adjustable positions withrespect to said housing about a generally horizontal aXis.

3. In the marine propulsion unit as defined in claim 2 wherein saidhousing includes a removable portion extending from adjacent the forwardend of said propeller toward the rearward end of said housing, said flowstraightening means being carried by said removable housing portion,said removable portion extending circumferentially about said propellersufiiciently to permit removal thereof from said housing after removalof said removable portion.

4. In the marine propulsion unit as defined in claim 3 wherein saidplurality of curved vanes comprises a pair of oppositely curved vaneportions defining a rudder carried by said removable portion andpivotally mounted on a -generally vertical axis on the same with thecurved vane portions =being each disposed at least in part within therearward end of said housing.

5. In a marine propulsion unit mounted on a planing boat having a sterntransom and a planing surface, a propeller shaft extending rearwardlythrough an opening in said transom, a propeller mounted on said shaft,at least a substantial portion of the propeller being below the at restwater line of the boat, a housing mounted on and fixed to the transomand extending rearwardly thereof, said housing including a portionclosely surrounding said propeller and extending rearwardly thereof toprovide a water Outlet for the housing, means providing a water inletopening in said housing forward of said propeller and below said planingsurface, and flow straightening means disposed rearwardly of saidpropeller and including a plurality of curved vanes mounted in selectedpositions within said housing and extending generally radially of andspaced angularly about the axis of said shaft with the curves thereoffacing and opposing the rotational component of the flowing water fromsaid propeller, said plurality of curved vanes including a pair ofoppositely curved vane portions defining a rudder pivotally supported bysaid housing on a generally Vertical axis with the curved vane portionsbeing disposed at least partially within the rearward end of saidhousing.

6. In a marine propulsion unit mounted on a planing boat having a sterntransom and a planing surface, a propeller shaft extending rearwardlythrough an opening in said transom and parallel to the centerline of theboat, the axis of said shaft being inclined downwardly and rearwardly ofsaid planing surface, a propeller mounted on said shaft rearwardly ofsaid transom with at least a substantial portion of the propeller Ebeingbelow the at rest water line of the boat and being partially below thegeneral plane of said planing surface, a propeller housing mounted onand fixed to said transom and extending rearwardly thereof parallel tothe longitudinal centerline of said boat, said housing including agenerally conical portion disposed co-axially over said shaft andclosely surrounding said propeller, said conical portion taperingrearwardly of the propeller and being provided at its rearward end withan outlet opening, and means providing a water inlet opening in saidhousing forward of said propeller and disposed below said planingsurface, the general plane of said inlet opening being inclinedsubstantially downwardly and rearwardly of said transom and inclineddownwardly to the general plane of said planing surface said flowstraightening means including a pair of oppositely curved vane portionsdefining a rudder supported by said housing on a generally Vertical axisand .2,11 1.6.3.815 partially disposed within the smaller diameter endof said conical portion vof said housing, tone of said curved vaneportions being disposed generaly above the axis of said shaft and theother of said vane portions being disposed generally =below the aXis ofsaid shaft. i

7. In a marine propulsion unit mounted on a planing boat having a sterntransom and a planing surface, a propeller shaft extending rearwardlythrough an opening in said transom, means in said boat for drivingsaidipropeller shaft selectively in forward and reverse direction, apropeller mounted on said shaft, at least a substantial portion of thepropeller being below the at rest water line of the boat, a housingmounted on and fixed to the transom and extending rearwardly thereof,said housing including a portion closely sur-rounding 'said propellerand extending rearwardly thereof to provide a water outlet for thehousing, means providing a water inlet opening in said housing spacedforward of said propeller vand below said planing surface, and flowstraightening means disposed rearwardly of said propeller and includinga plurality of curved vanes mounted in selected positions within saidhousing and extending generally radially of and spaced angularly aboutthe axis of said shaft with the curves thereof facing and opposing therotational component of the fiowing water from said propeller saidplurality of curved vanes including a pair of generally horizontallyextending oppositely curved vanes, and means mounting said vanes forselective adjustable positions with respect to said housing about agenerally horizontal axis, a pair of deflecting vanes constitutinginafirst position portions of the respective side walls of said housingforwardly of said propeller, means mounting each said vane for swingingon a respective upright axis, each vane having a rearward edge disposedrearwardly of its said upright swinging axis, and selective means forswinging said vanes to swing one and the other said vane from its saidfirst positions aligned in its said side wall into a reverse steeringposition wth its respectve rearward edge disposed nwardly of saidhousing thereby selectively to steer the boat when in reverse to portand starboard in response to corresponding lateral deflection of waterfrom said housing by the selectively nwardly swung vane. I`

8. In a marine propulsion unit mounted on a planing boat havig a sterntransom and a planing surface, a propeller, a propeller shaft extendingrearwardly through an opening in said transom and mounting saidpropeller, means including said shaft for driving said propellerselectively in forward and reverse direc'tions, at least a substantialportion of the propeller being below the at-rest water line of the boat,a housing mounted on and fixed to the transom and extending rearwardlythereof, said housing including a portion closely surrounding saidpropeller and extending rearwardly thereof to provide a water outlet forthe housing, means providing a water inlet opening in said housingforward of said propeller and below said planing surface, flowstraightening means disposed rearwardly of said propeller and includinga plurality of curved vanes mounted in selected positions within saidhousing and extending generally radially of and spaced angularly aboutthe axis of said shaft with the curves thereof facing and opposing therotational component of the flowing water from said propeller, saidplurality of curved vanes including a pair of oppositely curved vaneportions defining a rudder pivotally supported by said housing on agenerally Vertical axis with said oppositely curved vane portions beingdisposed at least partially within the rearward end of said housing,said housing comprising an opening on each respective side thereofforwardly of said propeller, two steering vanes having rearward edges,each said vane being pivotally mounted on a respective upright aXiswhich is forward of the rear edge of the respective vane to said housingin a respective said opening and each vane selectively swingable on suchaxis from a position closing its respective said opening to a postion inwhich its rearward edge is disposed inwardly of said housing to therebydirect a portion of the water flowing forwardly in said housing fromsaid propeller rotating in reverse direction laterally outwardly fromthe respective side of the housing, and steering means for swinging saidrudder and steering vanes.

9. The combination according to claim 8 wherein said steering meanscomprises means interconnecting said steering vanes and said rubber forswinging of both of said steering vanes and said rudder in unison in thesame directions.

10. The combination according to claim 8 wherein said housing isprovided with a narrow gas passageway defining the outer wall of thehousing under the propel- 1er and opening rearwardly below the wateroutlet of said housing, said passageway having upwardly and forwardlyextending branches along the sides of said housing, said branches havingupward forward ends adapted and arranged to receive engine exhaust gasesto be conducted by said branches and passageway for underwaterdisposition from said opening.

11. In a marine propulsion unit mounted on a planing boat and comprisingan elongated shell having side wa'lls and open forward and rearwardends, said shell defining a duct for the passage of water between saidends, a rotatable impeller in said duct spaced from said forward endthereof, means for driving said impeller selectively in a forwarddirection of rotation to impel water through said duct' from saidforward to said rearward end and in a reverse direction to impel waterfrom said rearward to said forward end, reverse steering meanscomprising means defining a side opening in each said side wall betweensaid impeller and said forward end, two deflecting vanes having reared'ges, said vanes being pivotally mounted to said shell at saidrespective openings for swinging on upright axes forward of the rearedge of the respective vane and said vanes being arranged to swing froma first position aligned with its respective side wall into a reversesteering position in which its said rear edge is disposed inwardly ofsaid duct and forwardly of said impeller to deflect water during reverseoperation of said impeller laterally through its respective saidopening, and means to swing each said vane selectively between its saidfirst and second positions.

12. The combination according to claim 11 wherein said shell is providedwith a rudder swingably mounted on an upright axis adjacent saidrearward end in the stream of water from said impeller when saidimpeller is rotated in said forward direction, and wherein said vaneswinging means interconnects said rudder and said vanes operative toswing said vanes and rudder together in one and the other direction.

13. The combination according to claim 11 wherein said shell is providedwith an external passageway having an upper forward portion adapted toreceive engine exhaust gases and extending from said portion generallydownwardly and rearwardly outwardly around a side of said shell passingrearwardly of said opening in said side and terminating rearwardly in anoutlet opening along a lower portion of the shell at its said rearwardend.

14. The combination according to claim 11 wherein said shell is providedwith a rudder swingably mounted on an upright axis adjacent saidrearward end in the stream of water from said impeller when saidimpeller is rotated in said forward direction, and wherein steeringmeans are provided for swinging said rudder on its said axis.

References Cited UNITED STATES PATENTS 1,676,150 7/1928 Mawby 115-12 X3,073,277 1/1963 Lee 115-12 3,159,134 12/1964 Winnen 115-12 TRYGVE M.BLIX, Primary Examiner.

U.S. C1. X.R.

